Spiral pipe machine



Dec. 24, 1968 G. L. CAMPBELL 3,417,587

SPIRAL PIPE MACHINE Filed Aug. 15. 1966 6 Sheets-Shea 1 INVENTOR.

GEORGE L. CAMPBELL ATTORNEY Dec. 24, 1968 G. L CAM PBELL SPIRAL PIPEMACHINE Filed Aug. 15. 1966 6 Sheets-Sheet 2 INVENTOR.

GEORGE L. CAMPBELL ATTORNEY Dec. 24, 1968 G. L. CAMPBELL 1 SPIRAL PIPEMACHINE Filed Aug. 15. 1966 6 Sheets-Sheet 5 74}. 6 1 N VENTOR'.

GEORGE L. CAMPBELL vii M ATTORNEY Dec. 24, 1968 G. L. CAMPBELL 3,417,587

SPIRAL PIPE MACHINE Filed Aug. 15. 1966 6 Sheets-Sheet 4 Infill Ulllflfimmwi INVENTOR.

I GEORGE L. CAMPBELL ,4 9 By ATTORNEY Dec. 24, 1968 v G. L. CAMPBELL3,417,587

SPIRAL PIPE MACHINE Filed Aug. 15, 1966 6 Sheets-Sheet 5 INVENTOR.GEORGE L. CAMPBELL ATTORNEY Dec. 24, 1968 G. CAMPBELL 3,417,587

SPIRAL PIPE MACHINE Filed Aug/l5. 1966 e Sheets-Sheet s INVENTOR.

GEORGE L. CAMPBELL ATTORNEY United States Patent 3,417,587 SPIRAL PIPEMACHINE George L. Campbell, Phoenix, Ariz., assignor to Garland SteelCompany Filed Aug. 15, 1966, Ser. No. 572,584 5 Claims. (Cl. 7250)ABSTRACT OF THE DISCLOSURE An improved machine for producing spirallock-seam pipe in which the diameter of the pipe is accuratelycontrolled by providing means for adjusting the lap of the locking seamsprior to crimping the seams into locking engagement.

This invention relates to improvements in spiral pipe machines.

More particularly, the invention concerns improvements in apparatus formanufacturing corrugated pipe having spiral corrugations.

In a further aspect, the invention relates to improvements in prior artspiral corrugated pipe machines, the improvements adapting such machinesto manufacture spiral corrugated pipe of accurately controlledpredetermined diameter.

In still another aspect, the invention concerns improvements in priorart spiral corrugated pipe machines which materially reduce thecomplexity of operation of the machine, such that such machines can beeffectively operated by less highly skilled workers or, alternatively,such that the operator training time required is significantly reduced.

Spirally corrugated pipe fabricated from metals such as galvanized steeland the like has achieved wide commercial acceptance within the last fewyears, particularly in the larger diameters where such pipe is used inthe construction of roadway culverts, waste and storm drainage sewers,irrigation conduits, and the like. Due to ease of handling and variouseconomic factors, spiral corrugated galvanized pipe is replacingconcrete pipe for many applications.

In general, spiral corrugated pipe is manufactured by rolling a flatstrip of metal stock into a sheet having longitudinal corrugations,bending the corrugated sheet spirally and joining the edges of thespirally bent sheet in some suitable fashion, for example, by forminginterlocking lips which are then crimped to form a spiral seam, or bywelding or by any other suitable means of joining the sides of thespirally bent sheet to form a spiral seam.

In one prior art machine for manufacturing such pipe, the longitudinallycorrugated sheet is forced into a solid die having a circular crosssection, the internal surface of the die having reverse corrugationswhich accom modate the corrugations of the strip being fed into themachine and which cause the strip to be bent spirally to the desireddiameter. The necessity of a different die for each desired diameter ofpipe and for each desired depth of corrugation for the same diameterpipe is an obvious disadvantage of this prior art machine. However, moreimportantly from the standpoint of the quality of the product, the priorart machine employing a die to bend the corrugated strip frequentlyscrapes away or otherwise damages the galvanic coating of a piece ofgalvanized steel, thereby rendering the pipe more susceptible tocorrosion and eventual failure under operating conditions.

In an attempt to remedy the deficiencies of the dietype pipe spiralingmachine, another machine was developed. In this later machine the spiralbending of the corrugated strip was accomplished 'by passing thecorrugated strip through a series of rolls which bent the strip into thedesired spiral configuration without subjecting the surfaces of thestrip to frictional engagement with various parts of the pipespiralingmachine. By appropriate adjustment of the position and pressure exertedby the various rolls, the diameter of the pipe could 'be varied asdesired, thus making it unnecessary to change parts of the machine inorder to produce pipes of varying diameter.

While the later roller-type pipe spiraling machine essentiallyeliminated the problem of damage to the galvanic coating of the pipewhich was encountered in the die-type machine, it introduced newproblems in that accurate control of the pipe diameter within thespecifications required for many applications of such pipe was extremelydiflicult. The diameter of the pipe produced by the roller-type machinewas almost never held constant but, rather, the pipe tended to grow orshrink as it was being formed and it required exceptional skill and longtraining and experience for the operator of such a machine to make thenecessary minute-by-minute corrections to maintain any semblance ofcontrol over the diameter of the pipe. In fact, the wide variation indiameter encountered in spiral corrugated pipe produced by therollertype machine severely limited the utility of such pipe,particularly where several sections of the pipe were joined to form anessentially liquid-tight conduit or where the diameter of the pipe hadto be accurately controlled in order to fit with other elements of astructure. In the attempt to furnish spiral corrugated pipe manufacturedby the prior art roller-type machine, it was often necessary that asmuch as 25% of the total production of the machine be relegated to thereject pile as unacceptable due to diameter variations.

It would be highly desirable to provide a spiral pipe machine whichproduces spiral corrugated pipe without the damage to the galvaniccoating induced by the use of a die-type machine and without the grossvariations in diameter encountered when the pipe was made by the priorart roller-type machine.

It is therefore a principal object of the present invention to providean improved spiral pipe machine.

Another object of the invention is the provision of a spiral pipemachine which does not damage the galvanic coating of the metal fromwhich the pipe is formed.

Another object of the invention is to provide an improved spiral pipemachine which fabricates spiral corrugated pipe of accurately controlledpredetermined diameter.

Still another object of the invention is the provision of such animproved spiral pipe machine which practically eliminates the productionof off-specification pipe which must be treated as rejects due todiameter variations.

A still further object of the invention is the provision of an improvedspiral pipe machine which can be operated by workers of less skill andexperience than was formerly required or, alternatively, which can beoperated by workers having a significantly reduced training period.

Still another object of the invention is the provision of an improvedspiral pipe machine which requires less time for adjustments andsubstitution of parts when changing the product size from one diameterto another.

These and other, further, and more specific objects and advantages ofthe invention will become apparent to those skilled in the art from thefollowing detailed description of the invention and the presentlypreferred embodiments thereof, taken in conjunction with the drawings inwhich:

FIG. 1 is a general perspective view of a roller-type spiral pipemachine in which the present invention may be advantageously embodied;

FIGS. 2-6 are a series of schematic drawings illustrat- 3 ing thegeneral mode of operation of the spiral pipe machine of FIG. 1;

FIG. 7 is a perspective view of the pipe-spiraling and lock-settingapparatus of the machine of FIG. 1;

FIG. 8 is a sectional view of the apparatus illustrated in FIG. 7 takenalong section line DD thereof;

FIG. 9 is a detail sectional view of a lock-setting apparatus embodyingthe present invention which is useful in conjunction with the devicesillustrated in FIGS. 18;

FIG. 10 is a detail plan view of the assembly for positioning the upperrolls of the apparatus of FIG. 9. For purposes of clarity ofillustration, a pair of longitudinal plates ordinarily positioned alongthe sides of the assembly have been omitted;

FIG. 11 is a cross-sectional view of the assembly of FIG. 10, thelongitudinal plates which Were omitted in FIG. 10 being included in FIG.11;

FIG. 12 is a sectional view taken along section line BB of FIG. 10,illustrating the engagement of the adjusting screw with the supportblock for the internal lockup wheel;

FIG. 13 is a perspective view of the lockup Wheel positioning plate ofthe assembly of FIG. 10;

FIG. 14 is a partial view of the lockup wheel of the assembly of FIG. 10and its associated support plate; and

FIG. 15 is a bottom view of the lockup wheel support plate viewed fromline CC of FIG. 14.

Briefly, according to my invention, I provide improvements in the priorart spiral pipe machine of the so-called roller type. This prior artmachine converts a longitudinally corrugated strip having locking lipson opposed Iongitudinal edges thereof into a circular pipe having spiralcorrugations. The prior art machine includes a spiraling apparatus forbending the longitudinally corrugated strip into a circular pipe and forengaging the locking lips to form a spiral seam, and a lock-settingapparatus for locking the engaged lips to maintain the circular shape ofthe pipe.

My invention comprises the improvement, in combination with the spiralpipe machine described above, whereby the diameter of the resultingcircular pipe can be accurately and conveniently controlled to apredetermined value, the improvements comprising means for adjusting thedepth of engagement (the lap) of the locking lips at the point where thecircular pipe is formed. Those Skilled in the art will understand thatthe terms depth of engagement and lap are synonymous and refer to theoverlap of the engaged portions of the locking lips as indicated by thereference character A on FIG. 9.

In the presently preferred embodiment of the invention, the means foradjusting the depth of engagement of the locking lips comprise a pair ofopposed lock-setting rolls located to position the engaged locking lipstherebetween and adapted to exert crimping pressure on the engagedlocking lips, thereby to lock the lips in engaged position and maintainthe circular shape of the pipe. One of the lock-setting rolls ispositioned internally of the pipe and the other of the lock-settingrolls is located externally of the pipe. At least one of thelock-setting rolls, preferably the internal roll, is adjustablylocatable axially of the pipe, thereby providing for adjustment of thedepth of engagement of the locking lips prior to crimping the lips intolocking engagement.

As will be apparent from the following detailed description, myinvention is to be carefully distinguished from the prior artroller-type pipe spiraling machine wherein neither of the lock-settingrolls could be adjustably located along the axis of the pipe beingformed to vary the depth of engagement of the locking lips as a means ofaccurately controlling the diameter of the pipe.

Turning now to the drawings, which will enable persons skilled in theart to better understand and practice my invention, FIG. 1 is aperspective view of a typical roller-type spiral pipe machine of theprior art. The machine generally comprises a storage roll 11 for acoiled strip of material such as galvanized steel. The flat strip 12 isfed from the roll 11 into the rolling mill, generally indicated byreference numeral 13, which comprises a plurality of pairs of opposedcorrugating rolls 14. As the strip passes through the successive sets ofcorrugating rolls 14, corrugations of successively greater depth arerolled into the sheet and locking lips are formed on the opposedlongitudinal edges of the strip.

The corrugated sheet 15 (indicated by dashed lines) passes from therolled mill 13 into the pipe-spiraling and lock-setting machine,generally indicated by reference numeral 16. The pipe-spiraling andlock-setting machine 16 includes a base member 17 supporting a yoke 18which, in turn, supports an internal mandrel 19 which carries a set ofinternal mandrel rolls 20. A set of external buttress rolls 21 and a setof external lead rolls (not shown) are also supported by the base member17. The corrugated strip 15 passes between the internal and externalrolls and is bent upwardly by the buttress rolls 21 in an are which,when closed, forms a pipe of the desired diameter. A plurality ofexternal support rolls 22 carried by the truss frame 23 support thecurved corrugated strip by maintaining radial pressure in the directionof the arrows 24. These support rolls assist in maintaining the curvedsheet in its proper position for entry into the lock-setting portion ofthe machine and, in addition, can be used to assist somewhat inmaintaining the desired pipe diameter. The curved corrugated strip 25now re-enters the machine for engagement of the locking lips and forpassage through the lock-setting portion of the machine. Afterengagement and locking of the locking lips, thus forming a circular pipehaving spiral corrugations and a spiral seam defined by the engaged andlocked locking lips, the pipe moves axially in the direction of thearrow 26 into the run-out and dump table portion of the machine,generally indicated by reference numeral 27. After the desired length ofpipe has been produced, a cut-off saw 28 operated by an electrical motor29 can be moved transversely of the run-out table in the direction ofthe arrow 30 to sever the desired length of the completed pipe.

The mode of operation of the spiral pipe machine of FIG. 1 isschematically illustrated in FIGS. 2-6. As the corrugated strip 31having locking lips on opposed edges leaves the rolling mill (not shown)in the direction of the arrow 32, it first encounters a set of leadrolls 33, as shown in FIG. 2. The periphery of the lead rolls 33 ride inthe concave surfaces formed by the corrugations and vertically supportthe strip 31. After passing the lead rolls 33, the strip 31 then ridesunder a series of internal mandrel rolls 34, as shown in FIG. 3. Theinternal mandrel rolls 34 and the lead rolls 33 position the corrugatedsheet 31 for subsequent bending and prevent buckling of the sheet in thearea therebetween. As shown in FIG. 4, the corrugated sheet 31, afterpassing the lead rolls 33 and the internal mandrel rolls 34, encountersthe buttress rolls 35 and is bent arcuately upwardly, inducing in thecorrugated sheet 31 a radius of curvature substantially corresponding tothe desired radius of the finished pipe. As shown in FIG. 5, thearcuately bent corrugated sheet 31a, after leaving the buttress rolls35, is positioned and supported by the external support rolls 36 whichexert pressure radially inwardly in the direction of the arrows 36a,thus forming the desired circular cross section. Finally, as shown inFIG. 6, the leading edge 31b of the corrugated sheet 31 passes between apair of lockup rolls 37 and 38 which crimp the now-engaged locking lipsforming a spiral seam which maintains the circular cross section of thepipe.

The planar schematic illustrations of FIGS. 2-6 will be betterunderstood by reference to FIG. 7 which is a general perspective view ofthe pipe-spiraling and lock-setting machine and which illustrates thegeneral mode of operation of the machine. The corrugated sheet 40,having locking lips on opposed longitudinal edges 41 and 42 thereof, isreceived from the rolling mill (not shown) and passes in the directionof the arrow 43 into the pipe-spiraling and lock-setting machine. Afterpassing the lead rolls and internal mandrel rolls (not shown), the sheetis bent arcuately upwardly in the direction of the arrow 44, therebyinducing a radius of curvature substantially equal to the desired piperadius. The sheet then passes arcuately downwardly as shown by the arrow45 and the locking lip of the outside edge 42:: is engaged with thelocking lip of the inside edge 41a. The engaged locking lips are thencrimped into locking engagement by the lockup wheels (not shown) thusforming the spiral seam 43. The pipe thus formed moves axially in thedirection of the arrow 44 to the run-out and dump table portion of themachine (not shown).

The operation of the various sets of rolls which perform the support,bending and lockup functions mentioned hereabove is further illustratedin FIG. 8. The lead rolls 51 comprise a plurality of individual rolls,the periphery of each of the lead rolls rides in the concave portions ofa corrugation in the corrugated sheet 52 received from the rolling mill.The corrugated sheet 52, supported by the lead rolls 51, then passesunder the internal mandrel rolls 53, which also comprise a plurality ofindividual rolls riding in the corrugations of the corrugated sheet 52and is bent arcuately upwardly in the direction of the arrow 54a by thebuttress rolls 54, which also comprise a plurality of rolls similar tothe lead rolls 51 and the internal mandrel rolls 53. The buttress rolls54 may be adjustably positioned horizontally as shown by the doublearrow 54b to vary the radius of curvature of the arcuately bentcorrugated sheet 52a. Also, the diameter of the pipe is effected by theangle 0 (indicated by reference numeral 55 on FIG. 7) between thecorrugated sheet 40 entering the pipe-spiraling machine and thelongitudinal axis of the pipe thus formed. Also, all sets of rolls canbe adjusted axially of the pipe to accommodate various widths ofcorrugated sheets and each of the individual rolls of the lead rolls,the internal mandrel rolls, and the buttress rolls can be angularlyadjusted to ride in the corrugations of the pipe or corrugated sheet asthe angle 0 (reference character 55 of FIG. 7) is varied to adjust thepipe diameter.

In the roller-type prior art pipe-spiraling and locksetting machine, theinternal lock-setting roll cooperating with the external lock-settingroll to crimp the engaged locking lips, thereby forming the spiral pipeseam, was integrally included as the endmost roll of the internalmandrel rolls. The axial, vertical and angular adjustment of theinternal mandrel rolls also governed the axial, angular and verticalposition of the internal lock-setting roll. However, according to thepresent invention, the depth of engagement of the locking lips prior tocrimping is adjustable because the position of the internal lock-settingroll can be adjusted independently of the internal mandrel rolls, aswill be explained in the description of the remainder of the drawings.This feature of adjustability of the internal lock-setting roll permitsone to continuously adjust and accurately maintain the desiredpredetermined pipe diameter without further gross adjustment of theentrance angle of the corrugated sheet into the pipe-spiraling machineor the horizontal position of the buttress roll. Formerly, these grossadjustments in entrance angle and horizontal position of the buttressroll were the only means available for controlling the diameter of thepipe being formed. These adjustments provided only very coarse controlof the pipe diameter and attempts to adjust the pipe diameter while themachine was in operation by variation of the pipe entrance angle orbuttress roll position induced growing or shrinking tendencies in thecircular corrugated pipe which seriously affected the quality of thepipe and the ability of the operator to maintain the desired diameterspecifications.

Referring to FIG. 9, which ShOWs in detail the method of varying thedepth of engagement of the locking lips,

according to a presently preferred embodiment of the invention, thecorrugated sheet 58 provided with locking lips 59 and 59a on opposedlongitudinal edges thereof is supported by the lead rolls 60 as itenters. the lock-setting machine and passes under the internal mandrelrolls 61 supported by the internal mandrel 62, After encountering thebuttress rolls (not shown) as described above and being bent arcuatelyupwardly to provide the desired radius of curvature, the bent sheet 63then passes downwardly and the outer locking lip 64 of the bentcorrugated sheet 63 engages the inner locking lip 59a of the corrugatedsheet 58 entering the machine. After engagement of the locking lips 64and 59a, the engaged lips pass between the internal lockup roll 65 andthe external lockup roll 66, which rolls crimp the engaged locking lipto form the spiral seam which maintains the arcuately bent corrugatedsheet in the form of a circular pipe having spiral corrugations.According to the presently preferred embodiment of the invention, thedepth of engagement of the locking lips 64 and 59a is controlled byvarying the axial position of the internal lockup roll 65 along a lineindicated by the double arrow 67. The specific mode of adjustment of theaxial position of the internal lockup roll 65 is illustrated in theremaining drawings.

As previously explained, in the prior art roller-type machines forproducing spiral corrugated pipe, the diameter of the pipe wascontrolled only by adjustments in the angle of entry of the corrugatedsheet into the pipespiraling machine and by adjustments in thehorizontal position of the buttress rolls. According to the presentinvention, the diameter of the pipe is controlled by first making thenecessary gross adjustments in entrance angle and buttress rollposition, and then adjusting the depth of engagement of the lockinglips, followed by further small changes in buttress roll position, ifnecessary. According to the presently preferred embodiment, theadjustment of depth of engagement of the locking lips is performed byadjusting the position of the internal lockup roll (reference numeral 65of FIG. 9). As will be appreciated by those skilled in the art, othermethods of adjusting the depth of engagement of the locking lips can beemployed to produce the same degree of control over the pipe diameter.Thus, in another embodiment of the invention, the external lockup roll(reference numeral 66 of FIG. 9) can be made similarly adjustable toprovide the desired adjustmerit of depth of engagement. It is thereforeto be understood that I do not limit the scope of my invention to anyspecific means for adjusting the depth of engagement of the lockingrolls. Rather, the invention, considered in its broader aspects, residesin the discovery that the diameter of the pipe can be accuratelycontrolled by varying the depth of engagement of the locking lips andthe specific means employed to accomplish this function can be varied tosuit the requirements of the individual machines involved and accordingto other relevant factors.

Turning again to the drawings which illustrate the presently preferredembodiment of the invention chosen for purposes of illustration, theparticular mode of adjustably positioning the internal lockup roll isillustrated in FIGS. l0l5, in which the reference numerals identify thesame elements in the various views. FIG. 10 is a detail plan view of theassembly for positioning the internal mandrel rolls of the apparatus ofFIGS. 1-9. The rolls are positioned on the underneath side of theinternal mandrel by means of a frame assembly comprising a floor plate70, longitudinal riser member 71 and longitudinal cap members 72. Theelements are maintained in assembled position by the cap screws 73positioned at spaced points along the sides of the assembly. Forconvenience of illustration, in FIG. 10 cap members 72 and cap screws 73are omitted. Referring specifically to FIG. 10, the internal mandrelrolls 74 (two shown) are positioned along the longitudinal axis of thefloor plate in abutting relation, the position of each roller beingmaintained by grooved locking inserts 75 which receive projectingrunners extending downwardly from the base members 76 which support eachof the internal mandrel rolls 74. Thus, the plurality of individualinternal mandrel rolls 74 is maintained in coequal angular position bythe grooved locking inserts 75 and will self-adjustably engage thecorrugations of the corrugated strip entering the pipespiraling machineat the proper entrance angle which is pro-selected to provide thedesired pipe diameter. The internal lockup roll 77 is mounted upon abase plate 78 which is received within the channel formed by the framemembers 70, 71 and 72 and is positioned within the channel independentlyof the internal mandrel rolls 74. The axial position of the internallockup roll 77 along a line indicated by the double arrow 79 is adjustedby means of an adjusting screw 80 acting upon a positioning block 81which has an arcuate groove 82 which receives an arcuate runner 82aprojecting downwardly from the internal lockup roller base 78. Theangular position of the internal lockup roll is adjusted and maintainedby means of an adjusting screw 81a acting upon a locking follower 82bhaving a cam face 83 which engages a cam surface 84 on the side of thebase 78.

Referring specifically to FIG. 11, which is a sectional view taken alongsection line AA of FIG. 10, the positioning block 81 is slidablyreceived in the channel formed by the floor plate 70, the longitudinalriser members 71 and the longitudinal cap members 72. A longitudinalhole 85 receives the adjusting screw 81a for the locking follower 82b. Aslot 86 having a downwardly projecting forward edge 87 is provided inthe face of the positioning block 81. This slot 86 receives a spoolpiece 88% on the end of the adjusting screw 80. This assembly is shownmore specifically in FIG. 12.

A more complete understanding of the general contours and shape of theadjusting block may be had by reference to FIG. 13 which shows the block81 provided with the arcuate groove 82.

FIGS. 14 and further illustrate the shape and various elements of thelockup roller base and lockup roller assembly. The base 78 is providedwith a downwardly projecting arcuate lip 82a which is received in thearcuate groove 82 of the positioning block 81. A vertical supportportion 88a extends upwardly from the base 78 and is drilled to receivea bearing support shaft 89 which carries the bearing 90 upon which theinternal lockup wheel 77 rotates.

The radius of curvature of the arcuate lip 82a is the distance r of FIG.15. The entire lockup Wheel baselockup wheel assembly rotates about avertical axis of rotation indicated by the crossed center lines 0. Thisline, extending upwardly, would pass through the periphery p of theinternal lockup wheel.

The invention herein described would, of course, be equally applicableto the production of smooth-wall spiral pipe, in addition to the spiralcorrugated pipe mentioned hereinabove. The invention provides a means ofaccurate control of the diameter of a pipe formed by bending orotherwise deforming a fiat sheet in a spiral and then joining the edgesof the spiral to form a spiral seam by engaging and crimping lockinglips on opposed edges of the sheet.

Various changes in the devices and methods chosen for purposes ofillustration in the drawings and specification will readily occur topersons skilled in the art having regard for the disclosure hereof. Tothe extent that such modifications and variations do not depart from thespirit of the invention, they are intended to be included Within thescope thereof which is not limited to the devices and methodsspecifically illustrated in the drawings and specification but, rather,only by a just interpretation of the following claims.

Having fully described the invention in such manner as to enable thoseskilled in the art to understand and practice the same, the inventionclaimed is:

1. In a spiral pipe machine for converting a longitudinally corrugatedstrip having locking lips on opposed longitudinal edges thereof into acircular pipe having spiral corrugations including a spiraling apparatusfor bending the longitudinally corrugated strip into a circular pipe andfor engaging said locking lips to form a spiral seam, and

a lock-setting apparatus for locking said lips to maintain the circularshape of said pipe, the improvements in combination therewith wherebythe diameter of the resulting circular pipe can be accurately controlledcomprising means for adjusting the lap of said locking lips at the pointwhere said circular pipe is formed.

2. Improved spiral pipe machine of claim 1 wherein the means foradjusting the depth of engagement of said locking lips comprises a pairof opposed lock-setting rolls located to position the engaged lockinglips therebetween and adapted to exert crimping pressure on said engagedlocking lips, thereby to lock said lips in engaged position to maintainthe circular shape of said pipe.

one of said lock-setting rolls being positioned internally of said pipe,and

the other of said lock-setting rolls being located externally of saidcircular pipe, at least one of said lock-setting rolls being adjustablylocatable axially of said pipe, thereby providing for adjustment of thelap of said locking lips prior to crimping said lips into lockingengagement.

3. Improved spiral pipe machine of claim 1 wherein the means foradjusting the depth of engagement of said locking lips comprises alock-setting roll located externally of the circular pipe and alock-setting roll positioned internally of said pipe, said internallypositioned lock-setting roll being adjustably rotatable axially of saidpipe, thereby providing for adjustment of the lap of said locking lipsprior to crimping said lips into locking engagement.

4. In a method of continuously producing spiral pipe comprisingarcuately bending an elongate sheet into a spiral shape and continuouslyforming a spiral seam by engaging locking lips located on opposed edgesof said elongate sheet and crimping said edges into locking engagement,the improvements in said method whereby the diameter of the resultingpipe is controlled to a predetermined value including the steps ofadjusting the lap of said locking lips prior to crimping them intolocking engagement, and

crimping said lips into locking engagement after adjusting the lapthereof.

5. Method of claim 4 wherein said adjustment of the lap of said lockinglips is accomplished by varying the axial position of lockup rollspositioned in opposed relation, one of said rolls being locatedinternally of said pipe and the other of said rolls being locatedexternally of said pipe.

References Cited UNITED STATES PATENTS 2,136,942 11/1938 Freeze 72502,862,469 12/ 1958 Jensen 72145 3,139,850 7/1964 Wiegel 72135 3,314,1414/1967 Bacroix 7249 CHARLES W. LANHAM, Primary Examiner.

K. C. DECKER, Assistant Examiner.

US. Cl. X.R. 72135

